Mainsail folding device for sailboats



FIG. 1 is a perspective view of a mainsail folding device for sailboats, showing my new design;

FIG. 2 is a side elevational view thereof, the opposite side elevation being identical;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof; and,

FIG. 5 is an end elevational view thereof, the opposite end elevation being identical. 

The ornamental design for mainsail folding device for sailboats, as shown and described. 